Although we've known it exists for decades, nobody knows exactly why there's a humming noise at the bottom of the ocean. But we're one step closer now that scientists have been able to record the sound underwater.

If you've ever been pulled underwater at the beach and came up sputtering with a mouthful of salt water, you might wonder where the ocean picked up that briny flavor. Read on to learn just where all that salt comes from.

There's still a lot we don't know about the world. A thousand years ago, we thought we could literally sail off the edge of the planet. Good thing we're quick learners. But while space may be the final frontier, the ocean may be the greater mystery.

There's no denying it: "Anomaly" is a great word, full of danger and mystery. So when an underwater object is declared a bona fide anomaly, it's no surprise our ears perk up a bit. But is the Baltic Sea anomaly worth the hype or just a big old dud?

Desalination has long been considered too expensive and too energy-intensive to make much sense. But with newer technologies, that line of thinking is changing. What are some of the most interesting desalination projects on the planet?